Connecting means for shielded ignition leads



J. W. ANDERSON CONNECTING MEANS FOR SHIELDED IGNITION LEADS Filed Nov. 1, 1943 May 6, 1947.

Patented May 6, 1947 CONNCTING MEANS FOR SHIELDED IGNITION LEADS John W. Anderson, Elizabeth, N. J., assigner, by mesne assignments, to Titeflex, Inc., Newark, N. J., a corporation of Delaware Application November 1, 1943, Serial No. 508,634

2 Claims.

This invention relates to the terminal arrangements and connections of a detachable radio shielded spark plug lead and the manifold and manifold conductor, of a radio shielded ignition harness for an internal combustion engine. It may, however, have other applications.

In radio shielded ignition harness of the wellknown conventional type there is `a manifold which conforms to the shape of the engine, being straight where the cylinders are arranged in straight rows and arc-shaped to embrace the engine shaft when the engine has its cylinders arranged radially as is usually the case in aeroplanes. The manifold is usually rigid and from it extend flexible spark plug leads to the various spark plugs respectively. A conduit also extends from the manifold to the distributor at the magneto, the manifold, spark plug lead conduits and manifoldV conduit being of metal and grounded. Ignition conductors or cables extend from the distributor through the magneto conduit and into the manifold and thence the individual conductors are connected through'the individual spark plug lead conduitsuwith the respective spark plugs.

Where the spark plug lead is detachably connected with the manifold, the manifold conductor extends into the conduit outside the manifold and leading to the spark plug, where it is prothe lead to the spark plug inflexible thereby depriving the flexible lead of much of the advantages of adjustability and adaptability which would be realized were the lead flexible at this portion. Especially is this true Where the distance between the manifold and a spark plug is small so y that the spark plug lead is relatively short and the rigid portion referred to constitutes a greater proportion of the length of the lead.

It is an important object of this invention to make flexible that portion of the lead to the spark plug above referred to as inflexible, so that such lead has the advantages of being fiexible substantially from the manifold outlet outwardly. This is accomplished by providing a flexible, metal, radio shielding conduit in place of the above referred to rigid sleeve, making its contained parts capable of flexing so that such lead portion may be flexed and combining such portion with the remainder of the spark plug lead and the manifold outlet.

A further object of the invention is to provide a greater distance of possible flash-over between the terminals referred to ,and ground for a given axial length of the conduit.

A further object of the invention is to economize material, lessen the weight and lower the cost of the lead by making the fiexible portion of the lead other than that containing the engaging terminals and appurtenant insulation, of less diameter than the iiexibie portion last mentioned whereby all the parts at the different points are accommodated without excessive use of material and the fiexibillty of the lead as a whole is enhanced.

A further object of the invention is to dispense with the `usual metal spring contact at the terminals by providing resilient terminal supporting insulation, pressing the terminals together in as'- lsembling and securing them in that relation whereby the insulation will be in a compressed condition and` its resilience will yieldingly press the terminals together.

A further object of the invention is to facilitate the assembling of the sparkplug lead with the manifold.

Other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawings which illustrate the invention- Fig. 1 is an elevation, partly in section and partly lbroken away, of a spark plug lead and a fragment of a manifold showing the connecting and terminal arrangement of a radio-shielded, detachable spark plug lead with the manifold and manifold conductor of a radio-shielded ignition harness for an internal combustion engine, which embody the invention, the parts being shown in assembled condition; and

Fig. 2 is a similar view of the apparatus as shown in Fig. l, but with the spark plug lead disassembled from the manifold and manifold conductor and with part of the spark plug lead, as shown in Fig. l, omitted.

Referring to the drawings, there yis, shown .y therein but a single spark plug lead and the igni tion cable therefor, with sufficient of a manifold to show the application of the invention, although it will be understood that the manifold will, in practice, have sufiicient cables and that there will be a spark plug lead branching therefrom for each spark plug served. The connections.A

however, of each spark plug lead with the maniiold may be as shown in the drawings.

The manifold comprises the metal arc-shaped, tubular portion I having an opening 2 and ineludes the metal nipple or outlet 3 about the opening, secured to the tubular portion I, such outlet having screw-threads l at its outer end and also the inwardly extending flange 5. A cable z .within the manifold is bent to pass outwardly .rough the opening 2 and outlet 3 and projects outwardly from the manifold. The cable comprises the flexible, stranded conductor 1 with the usual insulation B which leads back through the manifold and the magneto conduit (not shown) to the distributor atthe magneto (not shown).

About the cable 6 is a bushing of resilient, flexble insulating material such as rubber, a rubber compound, for instance, such as used by cable manufacturers in insulating flexible electric cable, or a suitable synthetic rubber compound h ais-neoprene. Such bushing comprises the oow S reeniorcing and locating the cable at its d the flange I0 resting upon the flange 5 oi' manifold outlet, whereby the bushing and .ets enclosed cable are supported, and the tapered cody il having the electric contact terminal Il its end connected to the cable conductor and overlapping the end of the body II. The bushing may ce molded on the cable or be pre-molded and the cable inserted therein.

The spark plug lead comprises a flexible, metal conduit I2 which may be a metal, strip-formed,

corrugated tube as shown in the Patent No. 1,198,- 392 to Louis H. Brinkman (see Fig. '7) covered with a braid of metal strips as shown in Fig. 5 of Patent No. 1,340,818 to said Brinkman. This conduit, at its spark plug end, is soldered to a metal elbow I3 provided with a nut for securing the elbow to the metal shield of a spark plug (not shown), a projection Il extending within the shield of the spark plug and having a spring I5 establishing contact with the central spark plus electrode. The spring I5 is connected with the conductor of a flexible cable I6 including the stranded, flexible conductor 2D covered with insulation 2| and passing through the elbow and conduit I2'. 'l'his construction and connection of the spark plugend of a lead is well known.

At the other end of the conduit I2 from the elbow, the conduit is soldered to a double ferrule 22, there being also soldered to this i'errule, the end of a flexible metal conduit I1 which is also a corrugated tube formed from a metal strip and with a braided covering of metal strips like the tube of the conduit I2', but the conduit I1 is of greater diameter than the conduit I2 to ahord space for the separable connections for the cables il and I6 and their appurtenant parts.

Within the conduit I1 and substantially filling the same except for the tapered recess about to be referred to, is molded a body I8 of resilient, insulating material, which may be rubber, a rubber compound, as for instance such as employed in insulating, flexible, electric cables, or a suitable synthetic rubber compound such as neoprone. The bushing I8 has a tapered recess IS in which the tapered body II is adapted t0 fit. The cable I6 enters into the conduit I1, passes through the insulation i8 and has its conductor connected with the electric contact terminal 23 in the bottom of the recess I9.

At the opposite end of the conduit I1 from the ferrule 22, a ferrule 24 surrounds the conduit.

The ferrule 2l has an inwardly and outwardly extending flange 25, the inwardly extending portion substantially covering the end of the conduit including the corrugated tube and its braided covering, while the outwardly extending portion is engaged by the flange of a nut 26 swiveling on the ferrule. The conduit I1, including both the corrugated tube and the braided covering, is securely soldered to the ferrule 24.

The conduit I2' may have molded in it an insulating compound filling the conduit about the conductor I6. Such illling may be the same material as that of the body I8 and is shown as being molded integral therewith.

In assembling the spark plug lead with the manifold, the body il is entered within the recess IS, the nut 26 is engaged with the threads I on the manifold outlet and when screwed down thereon clamps the ferrule flange 25 against the end of the conduit and the flange I0 of the bushing about the manifold conductor against the outlet flange 5. The parts are thus securely clamped in position with the spark plug lead firmly and securely attached to the manifold. The tapered body of insulation Il is made of such length and the parts are so proportioned and arranged that when the conduit I1 is clamped in position by the screwing down of the nut 2l, the terminals I2 and 23 are pressed together and their supporting resilient material is compressed and exerts a spring pressure holding the terminals in contact at all times so that a metal spring electrode for this purpose is unnecessary. Also it will be observed that the tapered engaging surfaces of the insulation bodies II and I8 provide greater security against flash-over from the conductor terminals to ground at the Joint betwen the` end of the body I8 and the flange I0 by increasing the distance from such terminals to such joint. The tapering of the body II of the bushing about the manifold conductor and of its corresponding recess in the body Il of the spark plug lead facilitates the entry of the body I I into the recess I9 in assembling the apparatus and holds the parts more firmly and securely together after assembly.

The conduit being flexible and its contained parts permitting flexing, it will be seen that the flexible length of the spark plug lead is greatly increased in comparison with the previous practice of having a rigid casing about the terminals of themanifold and spark plug lead conductors, and their appurtenant insulation. This increase in flexible length of the spark plug lead is of great practical value in increasing the adjustability and adaptability of the spark plug lead in assembling the harness upon the engine.

`Whle the invention has been illustrated in what is considered its best application it may have other embodiments without departing from its spirit and is not, therefore, limited to the structure shown in the drawing.

What I claim is:

1. The combination with the manifold of a radio shielded ignition harness for an internal combustion engine, said manifold having an opening, of a conductor in said manifold and projecting outwardly from said manifold through said opening, a second conductor for connecting with a spark plug, a zlexible metal radio shielding con duit into which said conductors enter, and means for securing said conduit to said manifold, a tapered body of flexible insulation within said conduit supported on the manifold and surrounding the conductor projecting from the manifold, the last mentioned conductor being supported by said insulation. a terminal at the end of said tapered body of insulation and connected with the first mentioned conductor, a second body of ilexible insulation Within the said conduit and through which said second conductor passes, said second body ofinsulation having a tapered recess within which the said tapered body of insulation extends and a second terminal connected to said second conductor at the bottom of said recess and engaging the first mentioned terminal.

2. The combination with the manifold of a radio shielded ignition harness for an internal combustion engine, said manifold having an opening, of a conductor in said manifold and projecting outwardly from said manifold through said opening, a second conductor for connecting with a spark plug, a exibie metal radio shielding conduit into which said conductors enter, means for securing said conduit to said manifold, a body of flexible insulation within said conduit, supported on the manifold and surrounding the conductor projecting from the manifold, the last mentioned conductor being supported by said insulation, a terminal at the rend of said body of insulation and connected with the first mentioned conductor, a second body of exible insulation Within the said conduit and through which said conductor passes, said second body of insulation having a tapered recess within which the first mentioned body of insulation extends and a second terminal connected to said second conductor at the bottom of said recess and engaging the first mentioned terminal.

JOHN W. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent: l

UNITED 'STATES PATENTS Number Name Date 2,316,504 Dayton Apr. 13, 1943 2,067,614 Mascuch Jan. 12, 1937 2,177,268 Stone Oct. 24, 1939 2,280,972 Paulson Apr. 28, 1942 2,186,038 Peters Jan. 9, 1940 2,275,762 Horton Mar. 10, 1942 1,981,460 Miller Nov. 20, 1934 2,123,162 Stone July 5, 1938 2,143,231 Stone Jan. 10, 1939 

